Cancer in Finland - Publications from the Cancer Society of Finland 2013 EEro Pukkala Matti rautalahti
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Cancer in Finland
Eero Pukkala
Matti Rautalahti
Publications from the Cancer Society of Finland 2013
Cancer in Finland Eero Pukkala and Matti Rautalahti
Cancer in Finland First edition in English ISBN 978-952-5815-16-0 ISBN 978-952-5815-17-7 (pdf) Cancer Society of Finland Publication No. 86 Translation from Finnish Luanne Siliämaa Layout and graphics Hannu Rinne and Jaana Viitakangas Atelier GraGra Publisher Cancer Society of Finland Printed by Erweko, Helsinki 2013 This book is based on the original edition published in Finnish Pukkala E, Rautalahti M, Sankila R. Syöpä Suomessa 2011. Suomen Syöpäyhdistyksen julkaisuja nro 82. Cancer Society of Finland, Helsinki 2011.
To the readers Cancer in Finland aims to give a balanced overview of cancer incidence, prevalence, and mortality in Finland. The report also presents current information on the causes of cancer and the pos- sibilities for cancer prevention. The Finnish Cancer Registry, an institute for epidemiological and statistical cancer research, was founded in 1952. At first, reporting of cancer cases was voluntary, but in 1961 the National Board of Health issued a by-law making reporting compulsory for all physicians, hospitals and other relevant institutions. Primary medical care in Finland is provided to the entire population at only a nominal fee. Every cancer patient receives adequate and modern treatment as required. Most of the information presented in this book is based on the comprehen- sive, high quality registration of cancers over the last 60 years and on the extensive epidemiological research done in Finland. Trends in cancer incidence have been studied in Finland for an exceptionally long time period. With the help of information from the registry files, many studies are done at the Finnish Cancer Registry on risk factors for cancer, prevention, and early diagnosis. The efficacy of the health care system has been followed using survival statistics of cancer patients. There are outstanding possibilities in Finland and in the other Nordic Countries for cancer re- search due to comprehensive data of high quality and the availability of data for research purposes. Employing and safeguarding these can be considered an important international obligation. Helsinki, June 2013 Nea Malila Professor, Director of the Finnish Cancer Registry
Contents Introduction 6 The Finnish Cancer Registry 6 Cancer Registration 7 Acknowledgements 7 Risk factors for cancer and their effect 8 Internal factors 8 Environmental exposures 10 Lifestyle 16 Socio-economic position 21 Cancer and other illnesses 23 Attributable fractions of risk factors 24 Possibilities for cancer prevention 24 Frequency of cancer in Finland 26 Changes in cancer frequency 26 Cancer and gender 35 Cancer and age 35 Differences between generations 40 Regional variation 40 Cancer screening 50 Cervical cancer screening 50 Screening for breast cancer 52 Colorectal cancer screening 53 Screening for prostate cancer 54 Screening for other cancers 54 Treatments 55 Survival 56 Factors contributing to survival 57 Years of life lost 59 Cancer in the future 62 References 69 How to find information about cancer on the Internet 76
6 | Cancer in Finland
Introduction
This publication deals with the occurrence of tion, there are a number of researchers working
cancer in Finland. The goal is to distribute in- on project-based funding.
formation related to cancer to those who have
something to do with cancer in their work or The Finnish Cancer Registry
studies, or to those who are otherwise interested
in the topic. The publication describes the fre- • produces descriptive information on the inci-
quency of cancer among different population dence, prevalence and mortality of cancer as
groups, risk factors for cancer, treatments for well as changes and predicted changes in the
cancer, the detection of cancer in pre-malignant situation;
and early stages through mass screening, the
survival of cancer patients as well as projections • produces countrywide and regional estimates
of cancer occurrence in the future. of cancer patient survival;
The publication is based for the most part on • acts as a specialist organization in questions
the data and results from the research work of related to cancer epidemiology and in the
the Finnish Cancer Registry. planning and evaluation of mass-screening
programmes and other actions against cancer,
The Finnish Cancer Registry and
The Finnish Cancer Registry is an institute for • researches the causes of cancer and the ef-
statistical and epidemiological cancer research fectiveness of treatments using epidemiol-
founded in 1952. In 2013 there were some 30 ogy and statistics, provides data to outside
permanent employees in the Cancer Registry: researchers and helps them in the planning
administrative personnel as well as experts in and execution of their studies.
medicine, epidemiology, and statistics. In addi-
Introduction | 7
Cancer Registration database and various other study materials col-
lected for the purpose of research. During the
The registration of cancers began countrywide existence of the Cancer Registry about 2000
in Finland in 1953. The National Board of scientific articles1 and some 200 doctoral disser-
Health requested at that time all doctors, hos- tations2 have been published in which Cancer
pitals and laboratories in Finland to report all Registry researchers or its data have had a cen-
information about cancer cases to the cancer tral role. Research related to the countrywide
registry that was overseen by the Finnish Can- mass screening programmes is performed in the
cer Registry. Notification of cancer cases has Mass Screening Registry, which is part of the
been compulsory since 1961. Finnish Cancer Registry.
Notifications from doctors, hospital and labo- Acknowledgements
ratories, as well as death certificate information
from Statistics Finland, are built into a database We thank Prof. Lauri Aaltonen from the
that is suitable for statistical use, and which University of Helsinki and from the Center of
produces graphs and other summaries. These Excellence on Cancer Genetics – in which ”Team
research materials are published as reports of Pukkala” from the Finnish Cancer Registry is
the Cancer Registry and as part of the official one of the five partners (Kaasinen et al. 2013)
statistics for Finland and the European Union. – and Prof. Jaakko Kaprio from the University
The Registry covers over 99 percent newly di- of Helsinki for updating the text on heritability
agnosed cancers and deaths from cancer in Fin- with the most recent references on this topic.
land since 1953 (Teppo et al 1994).
We also thank Dr. Harry Comber from the
Comprehensive statistical and epidemiologi- Irish National Cancer Registry for valuable
cal research is done on the basis of the Registry comments.
1
stats.cancerregistry.fi/Publications/publications.html
2
www.cancer.fi/syoparekisteri/en/general/doctoral-student-education
8 | Cancer in Finland
Risk factors for cancer
and their effect
Factors associated with a person’s lifestyle and cause symptoms. A single cause cannot be iden-
environment are significant in the development tified for the majority of cancer cases.
of many cancers but for some cancers genetic
characteristics may also be an important factor. Cancer is a complex group of diseases whose
In order to prevent cancer, it is crucially impor- causes, development, symptoms and treatment
tant to know those factors which influence the can differ greatly from one to another.
probability of developing cancer.
Internal factors
Risk factors for cancer can be roughly divided
into the following groups: Age. The majority of cancer cases are related to
the process of aging. During a long life, there is
• biological or internal factors such as age, gen- more time for exposure to the risk factors that
der, the metabolism of foreign substances in cause the cell mutations related to the develop-
the body, inherited genetic faults and skin ment of cancer. The longer a person lives, the
type more probable it is that his or her cells will ac-
cumulate cancer-causing damage. Aging also
• environmental exposures such as radon and weakens the cell’s ability to prevent and repair
ultraviolet radiation, as well as fine particles this damage.
• work-related exposures such as chemicals, ra- Gender. Gender-related characteristics (such as
dioactive materials and asbestos hormones) also influence the risk of cancers
other than those of the reproductive organs.
• lifestyle related factors such as physical activ-
ity and diet Heritability. A cancerous tumour or cell is not
contagious, nor is it passed from parent to child.
The development of cancer is a series of events As cancer is a common disease, approximately
occurring over many years, where the DNA of every third Finn will fall ill from cancer dur-
a normal, healthy cell is damaged. The cells ing his or her lifetime. Thus it is normal that
change, through many stages, into malignant in nearly every family there will be some can-
cells which grow independently of the normal cer patients, but this results from both genetic
regulatory systems of the tissues and finally and environmental influences. Susceptibility toRisk factors for cancer and their effect | 9
Figure 1
Cancer begins as a result of genetic mutations lasting many years after complicated series of events
that are influenced by numerous different environmental risks.
g g
g g g
Normal Mutated Stage 1 cancer Cancerous Confirmed
cell cell / cancer’s first tumour cancer
stage
Exposure risk factors for cancer such as chemicals,
viruses or radiation.
g Cell level change
cancer (an increased risk of developing cancer) organ presents in several affected family mem-
can be inherited. This means that one or more bers. Young age at onset, and the occurrence
inherited gene defects relevant to the develop- of multiple primary tumours, are also features
ment of cancer are already in place in all of the suggestive of hereditary predisposition. Domi-
person’s cells, and they can be passed on to off- nantly inherited susceptibility is passed on to
spring through the germ line. an average of every second offspring. If a mem-
ber of a family with hereditary susceptibility
While in rare cases a single gene defect may lead has not inherited the faulty gene(s), his or her
to a greatly increased risk of cancer, it is much children do not have an increased risk of cancer.
more common that there are multiple gene de- These types of cancer are rare and account for
fects, each contributing a minor increase in risk. only a small fraction of all cancers.
Depending on the inherited combination of
such genes, inherited susceptibility may be larg- However, most common cancers have some
er or smaller. In addition to such defects, envi- hereditary component, including breast and
ronmental risk factors are also required to cause intestinal cancers, thyroid cancer, uterine and
the additional changes in the cells necessary for ovarian cancers as well as prostate cancer, based
the development of a malignant tumour. on analyses of large twin cohorts (Lichtenstein
et al 2000). In the past five years, genome-wide
For cancers where there are only a single or few studies have discovered tens of genetic loci as-
gene defects it is typical that cancer of the same sociated with increased risk of common cancers10 | Cancer in Finland
such as prostate (Amin et al 2012, Eeles et al Environmental exposures
2013) and breast cancer (Pylkäs et al 2012,
Solyom et al 2012, Bojesen et al 2013, French et Residential pollution. Impurities in the air and
al 2013, Garcia-Closas et al 2013, Michailidou emissions from nearby industry and traffic in-
et al 2013). crease, to some extent, the risk of lung cancer.
Differences in the incidence of cancer in dif-
Cell level changes in cancers related to heredi- ferent parts of Helsinki, however, are not con-
tary predisposition have begun to be better un- nected to sulphur or nitrogen oxide emissions,
derstood through molecular genetic research. nor to traffic volumes (Pönkä et al 1993). Lung
Finland offers excellent possibilities for research cancer in men appears most frequently in those
on hereditary susceptibility, and because of this parts of Finland where the air is clean. Thus,
many internationally recognised research pro- air pollutants are insignificant risk factors com-
jects have been carried out here (Peltomäki et pared to tobacco.
al 1993, Aaltonen et al 1998, Hemminki et al
1998, Aarnio et al 1999, Matikainen et al 2000, In the production of drinking water, the chlo-
Olsen et al 2001, Eerola et al 2001, Tomlinson et rination of surface water produces compounds
al 2002, Vierimaa et al 2006, Erkko et al 2006, that can cause mutations which may slightly
Georgitsi et al 2007, Alhopuro et al 2008, Tuu- increase the risk of bladder cancer, for example
panen et al 2009, Sur et al 2012). (Koivusalo et al 1997). Arsenic in drilled wells
appears to have the same kind of effect (Kurttio
Genetic tests have been developed for diagnos- et al 1999). In a village in Southern Finland,
ing hereditary susceptibility. Some of these are chlorophenol in the ground water was estimat-
still only in research use while others have been ed to have caused approximately one additional
implemented for clinical use. There remain a cancer case every two years (Lampi et al 1992)
number of unsolved problems with regard to during 1972–1986; there was no excess risk
the relevance of genetic testing, interpretation following closure of the old water intake plant
of the results and counselling of at-risk individ- (Lampi et al 2008). Another study is investigat-
uals. The identification of multiple genes, each ing, among other things, whether dioxins from
having a small effect on risk, poses particular a river in south-eastern Finland increase the risk
challenges for clinical use. of cancer for people who eat fish containing di-
oxins from that river (Verkasalo et al 2004).
The Cancer Society’s advisory services (also
website www.neuvontahoitaja.fi, in Finnish) Another target of investigation in environmen-
offer advice to persons concerned about he- tal health have been residents of buildings con-
reditary susceptibility to cancer. For many of structed over the garbage dump in a residential
the hereditary cancer syndromes management area of Helsinki. According to the first results,
strategies for prevention and early detection are slightly more cancer and asthma were diagnosed
available, and cancer incidence and mortality in the residents than in residents of comparable
can be reduced in at-risk individuals. buildings (Pukkala and Pönkä 2001), but basedRisk factors for cancer and their effect | 11
on the latest research, the people who lived in tions are intended to ensure that the exposure
those – now demolished – buildings have not of workers to asbestos remains as small as pos-
had any more cancers than others in Helsinki sible. Despite this, for those who have done
after 1999. asbestos spraying work, the risk of developing
mesothelioma and lung cancer is still greater
In recent years, there have been more measure than for the rest of the population (Oksa et
ments of the environmental situation, and with al 1997). Tobacco has, however, proven to be
their help, we can better evaluate the asso- many times more important as a cause of can-
ciation between environmental pollutants and cer than asbestos. The risk of lung cancer for a
cancer risk. non-smoking asbestos worker is only 1.4 times
that of a non-smoker not exposed to asbestos.
Occupational hazards. The influence of work- However, a smoker not exposed to asbestos has
related hazards, such as chemicals, on the risk a 14-times greater risk, and a smoker exposed
of cancer has been identified in hundreds of to asbestos has a 17-times greater risk, of lung
different studies. The web page of the Finn- cancer. Almost all mesotheliomas are caused by
ish Institute for Occupational Health (www. asbestos (Meurman et al 1994).
occuphealth.fi) has good information about
cancer risks resulting from occupational envi- Exposures considered to be relatively safe in
ronment hazards and about their measurement. the working environment may change into
significant risk factors, if they occur together,
In the Cancer Registry, research has been done for example, with tobacco use. The Finnish Job
over many decades on the risk of cancer, among Exposure Matrix (FINJEM), developed by the
others, for healthcare personnel, workers in Finnish Institute of Occupational Health, helps
the chemical wood processing industry and to estimate exposures to different chemicals and
sawmill industry, employees in the printing other factors for workers in different occupa-
industry, shipyard workers and machinists, oil tions. With its help, we can estimate quantita-
refinery employees, glass and glass fibre work- tive amounts of exposure to carcinogenic factors
ers, shipping personnel, airline personnel, train for every person in the population (Pukkala et
engineers, farmers, bush insecticide sprayers, al 2005). Currently, comparable estimates can
hairdressers as well as employees exposed to be made for the populations of all Nordic coun-
asbestos, styrene, trichloroethylene, formalde- tries (Kauppinen et al 2009).
hyde, PCB, lead, nickel and other metals. Many
of these worker cohorts are still being followed. Large variations in cancer risk in different oc-
cupational categories have been demonstrated
Asbestos is considered to be an important fac- in the large Nordic Occupational Cancer Study,
tor in increasing the risk of cancer in the work- NOCCA (astra.cancer.fi/nocca) which studied
ing environment, and that is why, for example, the risks for cancers associated with different
clear regulations have been given for the repair occupations.
and demolition of older houses. The regula-12 | Cancer in Finland
Figure 2
Occupations with the lowest and highest incidence of cancers in men in the Nordic countries
1961–2005 (Pukkala et al 2009).
Mesothelioma
Farmers Plumbers
Pharynx cancer
Farmers Waiters
Oral cancer
Farmers Waiters
Liver cancer
Farmers Waiters
Tongue cancer
Farmers Waiters
Lip cancer
Doctors Fishermen
Laryngeal cancer
Farmers Waiters
Oesophageal cancer
Doctors Waiters
Lung cancer
Nurses Waiters
Nasal cancer
Military workers Wood workers
Skin melanoma
Fishermen Dentists
Gastric cancer
Dentists Fishermen
Skin, squamous cell carcinoma
Forestry workers Nurses
Bladder cancer
Farmers Waiters
Gallbladder cancer
Farmers Laundry service
Testicular cancer
Forestry workers Doctors
Pancreatic cancer
Farmers Beverage workers
Non-Hodgkin lymphoma
Chimneysweeps Tobacco industry
Kidney cancer
Nurses Tobacco industry
Colon cancer
Forestry workers Chimneysweeps
Prostate cancer
Domestic assistants Dentists
Rectal cancer
Nurses Waiters
Central nervous system cancer
Chimneysweeps Physicians
0.3 0.5 0.7 1.0 2.0 3.0 5.0
Standardized incidence ratioRisk factors for cancer and their effect | 13
Table 1
Occupations with the highest and lowest cancer incidence in Finland 1971–2005: Standardized inci-
dence ratios (SIR) that are statistically significantly increased in relation to the mean in the population
(SIR = 1.00) are highlighted in red and those which are decreased in green (Pukkala et al 2009).
N = number of cancers.
MEN WOMEN
Occupational category N SIR Occupational category N SIR
Tobacco industry work 26 1.30 Military work 20 1.36
Mine work 1 398 1.28 Security work 175 1.27
Seafarers 1 742 1.19 Dentists 440 1.22
Waiters 251 1.15 Physicians 438 1.19
Construction work 10 939 1.14 Traffic work 677 1.17
Assistant nurses 38 1.12 Directors 1 507 1.14
Plumbers 2 488 1.11 Journalists 434 1.12
Packers 5 670 1.11 Building hands 897 1.12
Cooks and head waiters 252 1.10 Technical, scientific, etc. work 1 651 1.11
Teachers 8 093 1.11
Chemists and laboratory assistants 894 1.10
Nurses 4 543 1.10
Office work 26 565 1.10
Tobacco industry work 95 1.10
Farmers 6 526 0.90
Drivers 262 0.89
Fishermen and hunters 42 0.88
Wood work 1 803 0.88
Welders 78 0.87
Farmers 38 820 0.90 Gardeners 18 024 0.86
Gardeners 5 174 0.87 Mine work 31 0.81
Teachers 4 914 0.84 Beverage industry 120 0.79
Dentists 132 0.78 Seafarers 9 0.71
Barbers, hairdressers 54 0.78 Bricklayers 17 0.60
Domestic assistants 4 0.24 Forestry work 50 0.5314 | Cancer in Finland
The NOCCA study confirms known connec- ar bombs in the 1950s. Radiation particularly
tions between occupational factors and cancer, increases the risk of leukaemia, thyroid cancer,
but points in addition to the influence of life- breast cancer, lung cancer and bladder cancer.
style related choices such as use of tobacco and
alcohol. The increase in office work reduces The most important source of radiation among
work-related physical activity, which would the Finnish population is radon in indoor air,
protect against cancer. Shift work is now also with a dose averaging 2 mSv received annu-
seen to be a probable cancer risk factor (Straif ally, which is about half of the total radiation
et al 2009). Ultraviolet rays from sunlight are a received by Finns. Alpha radiation produced by
significant risk for certain occupations: for ex- radon does not penetrate material deeply, and
ample lip cancer is found particularly often in therefore inhaled radon results in radiation ex-
fishermen and farmers, while the risk of skin posure only to the lung. The only clearly estab-
melanoma is greatest for indoor workers whose lished health impact of radon is increased lung
skin is not accustomed to the sun and burns cancer risk. In an extensive European study, also
easily on holiday. involving Finnish researchers, the proportionate
increase in lung cancer risk was 8 percent (Dar-
The greatest cancer risk for Finnish men is in the by et al 2005) at a concentration close to the av-
tobacco industry and in mining work (Table 1). erage in Finnish houses (100 Bq/m3). Radon in
The occurrence of cancer for those working in indoor air is estimated to cause about ten per-
these areas is about thirty percent more than cent of lung cancer among Finns or about two
the average for Finnish men. hundred lung cancer cases every year, which is
far less than that attributable to smoking but
The biggest cancer risk for Finnish women is comparable to the burden from e.g. environ-
in military and security work, which also in- mental tobacco smoke.
cludes women working as police officers or as
security guards. Next on the list are dentists and In diagnostic radiology the benefits of inves-
doctors. There is a significantly less-than-aver- tigations using x-rays need to be considered
age cancer risk, for example, for women forest relative to the small risk caused by radiation
workers and bricklayers. exposure. Occupational groups exposed to ra-
diation include, for example, radiologists, x-ray
Radiation. Ionizing radiation is ubiquitous, be- technicians or nurses and nuclear power plant
cause radiation is produced, for example, by workers. The radiation doses received by these
natural radioactive materials in the Earth’s crust. groups nowadays are generally rather small. No
Ionizing radiation has been estimated to cause increased cancer risk has been shown among
1–3 percent of all cancers. X-rays were found to Finnish nuclear power station workers or phy-
cause cancer in the early 1900s. Strong scien- sicians occupationally exposed to radiation
tific proof that small doses increase the impact (Auvinen et al 2002, Jartti et al 2006). The pro-
of radiation risk was obtained from research on duction of nuclear energy in normal circum-
survivors of the Hiroshima and Nagasaki nucle- stances causes radiation exposure, in practice,Risk factors for cancer and their effect | 15
only to workers, and no excess of cancer has Figure 3
been found around nuclear power stations in Doses of radiation among reindeer herders and
Finland (Heinävaara et al 2010). The nuclear other people in northern Finland in 1950–2005.
power station disaster in Chernobyl in 1986 re- Those who had eaten the most reindeer meat
sulted in some additional radiation to nearly all did not have more cancer than others (Kurttio et
Finns. The dose, even at its largest, was only the al 2010).
same as that received annually from other natu-
ral sources (about 1 mSv). Leukaemia among
children or thyroid cancers did not increase af-
ter the accident (Auvinen 1994, But 2006), nor µGy
did the fallout from atmospheric nuclear tests 2.0
in the 1960s result in a detectable excess of can-
cer in the most heavily exposed population of Reindeer herder
Northern Finland (Figure 3, Kurttio et al 2010).
1.5
Cancer patients receiving radiation therapy are
exposed to very high radiation doses, and in ad-
dition to the tumour, the surrounding tissues
1.0
are also affected. Patients treated with radiation
therapy involving substantial doses to the bone
marrow have an increased risk of leukaemia and
other cancers (Travis et al 2000, Worrillow et al 0.5
2003, Hill et al 2005, Salminen et al 2006 and
2007), but the benefits of treatment clearly out-
weigh the risks. Other
0
Cosmic radiation is sparse at sea level, but in- 1950 1960 1970 1980 1990 2000 2010
Year
creases with altitude. Exposure to cosmic ra-
diation is considerable in air travel, but the in-
creased breast and skin cancer risk among pilots
and flight attendants is not related to the radia-
tion dose (Pukkala et al 1995, 2002 and 2012).
Non-ionizing radiation does not have sufficient
energy to remove electrons from an atom. It in-
cludes ultraviolet radiation as well magnetic and
electric fields. Ultraviolet radiation is received
from the sun and solarium and causes skin can-
cer. The most important cause of melanoma is16 | Cancer in Finland
intensive UV-radiation to skin unaccustomed ing in Finland, Sweden, Denmark, Great Brit-
to this, causing burning of the skin, particularly ain and the Netherlands.
in children and adolescents. In particular, light
skinned, blue-eyed people and those who burn Lifestyle
easily and tan poorly are at risk. Some melano-
mas occur in moles, and having a large number Tobacco. The use of tobacco products is the
of moles (over 100 pigmented naevi) increases most important single factor that increases can-
melanoma risk. cer risk. The risk from tobacco is based on a
large amount of carcinogenic (cancer-causing)
Power lines and electrical appliances generate compounds, which are already in tobacco prod-
low frequency magnetic fields (50–60 Hz). ucts or are formed during the burning process.
The impact on cancer risk, and particularly on
childhood leukaemia, has been studied exten- It has been estimated that tobacco products
sively, and increased risk estimates for child- cause one third of all cancers. The impact of
hood leukaemia, related to very high exposure smoking on lung cancer is the best known. The
levels, have been shown in several studies. For probability of getting lung cancer is greater the
other cancers, no clear indication of excess risk younger a person starts smoking, the more the
has been demonstrated. According to Finnish person smokes daily and the longer the smok-
research series covering the entire population, ing continues (Hakulinen and Pukkala 1981). If
children and adults do not have an increased a person has smoked 20 cigarettes daily for 50
cancer risk related to proximity to power lines years, his or her risk of getting lung cancer is 50
(Verkasalo et al 1993 and 1996). Occupational times higher than that of non-smokers. After
exposure to electromagnetic fields occurs in stopping smoking, the danger of lung cancer
many workplaces, but there is no indication of quite rapidly approaches the lung cancer risk of
cancer risk as a result of such exposures. a non-smoker of the same age, but never drops
to the same level. Those who have smoked for a
Radar, radio transmitters, mobile phones and long time will still benefit the most from stop-
base stations, among others, generate radiofre- ping smoking.
quency electromagnetic fields (in the megahertz
range). Radiofrequency fields do not cause ge- Smoking is a significant cause of laryngeal can-
netic changes, and have not increased cancers cer, and is also linked to cancers of the mouth,
in animal tests. In epidemiologic research, the throat, kidney, pancreas, oesophagus, uterus
use of mobile phones has been linked to an and bladder. Smoking may also increase the risk
increased cancer risk (Interphone Study Group of breast cancer (Xue et al 2011).
2010), but problems with this research include
a fairly short ten-year follow-up period and the In 2009, 22 percent of Finnish men and 16 per-
unreliability of information on mobile phone cent of Finnish women smoked daily (Helakor-
use based on questionnaires. More reliable evi- pi 2010). In addition, about 8 percent of adults
dence is expected from follow-up studies ongo- smoked occasionally. Smoking among menRisk factors for cancer and their effect | 17
has been decreasing for decades, but smoking Figure 4
among women has begun to reduce slightly Age-adjusted (world) incidence of lung cancer
only in the last few years. There are major dif- in Finland and Norway 1953–2009.
ferences between social groups in the frequency
of smoking, and these differences continue to
grow. Fifteen percent of men with a higher level
of education, but 37 percent of men with the Incidence/100 000
90
lowest level of education, are smokers. At least
two out of three smokers have attempted to
80
stop smoking.
70
Snus is being used daily by 1.7 percent of Finn-
ish men and 0.1 percent of women (Helakorpi 60
et al 2011). Recent research has indicated a
50
clear cancer risk resulting from using snus. The
danger of cancers of the mouth, throat, pan- 40
creas, stomach as well as oesophagus is much
greater in those using snus than those not using 30
tobacco products (Luo et al 2007, Roosaar et al
20
2008, Zendehdel et al 2008).
10
The prevalence of lung cancer in Finland’s
male population has been among the highest 0
in the world, and 20 years ago it was five times 1950 1960 1970 1980 1990 2000 2010
Year
higher than that in Norwegians. This big diffe • Norway: men • Norway: women
rence was explained by different smoking habits • Finland: men • Finland: women
some decades ago (Hakulinen et al 1987). Lung
cancer develops only decades after the smoking
started, and therefore lung cancer incidence re-
flects the smoking habits of 20–50 years ago.
Nowadays Norwegians have more lung cancer
than Finns (Figure 4).
Exposure to cigarette smoke in the environment
increases the risk of lung cancer. It has been es-
timated that involuntary smoking causes 10–50
new lung cancers every year in Finland. Invol-
untary smoking in previous decades may be one
of the explanations for the fact that restaurant18 | Cancer in Finland
workers have the highest cancer risk of all oc- cancer risk does not differ significantly with
cupations in the Nordic countries (Pukkala et the type of alcohol drink consumed. The most
al 2009). important risk factor is the amount of ethanol
consumed.
Cancer risk often increases significantly through
the combined impact of smoking and some Alcohol, or ethanol, may cause cancer through
other factor. Smoking and outdoor work to- several possible mechanisms. The most sig-
gether increase increase for instance the risk of nificant is probably that, in the body, alcohol
lip cancer by 15-fold, although outdoor work breaks down into acetaldehydes, which are
alone or smoking increases lip cancer risk only capable of causing DNA damage (Salopuro
by two-fold (Lindqvist 1979). Correspondingly, 2009). In addition, the breakdown of alcohol
smoking increases the impact of asbestos and blocks the body’s removal of toxins and makes
many such materials used in the working en- it possible for the other cancer risk factors to ac-
vironment, which alone are not particularly cumulate in tissues. Alcohol is also an efficient
dangerous. solvent, which may harm mucous membranes
from the mouth to the stomach and, therefore,
Alcohol. There is a clear causal relation between make it possible for other substances to have an
the use of alcohol and several cancers. There is influence.
convincing evidence that the use of alcohol in-
creases cancers of the mouth, throat, larynx, Dietary factors. The effects of diet on cancer
oesophagus and liver (Baan et al 2007, www. have been researched intensively for decades.
dietandcancerreport.org). Thirty years ago it was estimated that diet was
the most important modifiable cause of cancer.
Four daily servings of alcohol (50 g ethanol), for Diet is a complex mix of components in which
example, increase the risk of mouth and phar- combined and contradictory effects are difficult
ynx cancers by two-fold. Other factors may in- to understand.
crease the impact of alcohol. Drinking alcohol
and smoking together very strongly increase the Diet has been considered to have the strongest
risk of cancers of the mouth, throat and larynx. influence on the risk of cancer of the stomach,
colon, rectum, as well as the oesophagus, kidney,
With regard to breast cancer, there is no safe bladder, prostate, lung, breast and corpus uteri.
amount of alcohol intake, but rather the These are common cancers in Finland and other
risk of cancer increases directly in relation to countries with western diets. Dietary factors can
the amount of alcohol consumed. Moderate cause cell transformations in many ways:
amounts of alcohol taken infrequently are not
significant. On the other hand, excessive use of • Some dietary factors can in themselves cause
alcohol increases the cancer risk and causes oth- cancer (for example alcohol).
er clear health problems regardless of whether
drinking alcohol is infrequent or regular. The • Cancer causing substances can be found inRisk factors for cancer and their effect | 19
food which is spoiled or not clean (for exam- Many of these vitamins are important antioxi-
ple aflatoxin of certain moulds). dants in the body. They prevent oxidation of
fatty acids and protect the body from harmful
• In some methods of preparing food, cancer- substances arising from oxidation. Low levels of
causing substances are formed (for example vitamin D seem to be linked to an increased
polycyclic aromatic hydrocarbons when grill- risk of some cancers, but high levels of vitamin
ing). D are also linked to a higher than usual cancer
risk (Tuohimaa et al 2007).
• Certain dietary factors can become cancer-
causing in the body (nitrites). Several studies have indicated that a diet rich in
vegetables and fruit decreases the risk of many
• The lack of dietary factors which are protec- cancers. Vitamin products have been also re-
tive against cancer (for example a lack of vi- searched in cancer prevention experiments, but
tamins and minerals) increase the risk of get- none have so far been proven to prevent cancer
ting disease. alone or in combination (ATBC 1994). It is
probable that from the point of cancer preven-
A diet that has an excessive energy content, or tion, a balanced totality, not single nutrient fac-
the resulting excess in body weight, increases tors, is the most crucial aspect of diet.
the risk of many cancers. Based on many ani-
mal experiments, it has been found that fat Among the minerals, selenium has been the
in the diet increases the risk of cancers of the most researched. It is estimated that a lack of
breast, colon and pancreas. Information con- selenium increases cancer risk. The selenium
cerning humans is not yet so convincing that content of Finnish food is nowadays sufficient;
dependable conclusions could be drawn on therefore additional selenium products are not
the impact of fat in the diet on the cancer risk. needed.
Cancer tissue also needs energy and minerals,
and therefore, dietary factors can – as well as Some food preparation methods cause chemi-
causing cancer – also influence the growth of cal changes that lead to cancer-causing factors.
cancer. Smoking and grilling fatty food on an open
fire or otherwise at a high temperature creates
Dietary fibre probably protects against colon small amounts of polycyclic aromatic hydrocar-
cancer (Bingham 2003). Hence root vegetables bons (PAH) on the surface of the food, which
and rye bread, which belong to the traditional increase the cancer risk. Acrylamide in potato
Finnish diet, are also healthy in this regard. chips, French-fries and hard bread is classified
as a possible cancer risk compound, but eating
Vitamins are one of the most important areas food containing acrylamide has not been found
of research concerning links between food and to have a connection to cancers (Mucci et al
cancer. The greatest interest has been in carot- 2003). Excessive use of food preserved by salt
enoids, A, E, C and D vitamins and folates. increases the risk of gastric cancer.20 | Cancer in Finland
Exercise and weight control. A link between ex- Reproduction and hormones. Cancer of wom-
ercise and cancer risk has been observed in sev- en’s reproductive organs and breast cancer are
eral studies. Scientific proof has been collected clearly linked to sexual and reproductive behav-
of the protective effects of exercise, particularly iour. If a woman herself – or her sexual partner
concerning cancers of the breast, colon, uterus – has had several partners, she is more likely
and prostate (www.dietandcancerreport.org). than other women to get cervical cancer. The
explanation for this is that sexually transmitted
Moderate exercise changes the metabolism of viruses are important factors in cervical cancer
certain hormones and strengthens the func- (see Infections).
tioning of the body’s general protective mech-
anisms. Exercise reduces the amount of fat Giving birth at a young age and having many
tissue, and the amounts of different growth children protect from breast cancer. The pro-
factors become more balanced. The diet of an tective impact is increased if a woman has many
actively exercising person often includes more children (Hinkula et al 2001). Not having chil-
components that protect from cancer. dren is also a risk factor for cancers of the ovary
and corpus uteri, and early sexual maturity and
According to the latest research, the benefits of late menopause increase the number of a wom-
exercise are generally achieved by about an hour an’s menstrual cycles and increase the risks of
of daily exercise, such as walking or cycling to the above-mentioned cancers.
work or to the shops, going up the stairs or rak-
ing the yard. For weight control, it is sufficient Modern contraceptive pills protect against can-
to have half an hour of exercise three times a cers of the ovary and corpus uteri. During men-
week. Those doing office work in particular opause, women who have undergone lengthy
should exercise regularly in order to avoid being hormone therapy are, on the other hand, diag-
overweight. Brisk exercise several times a week nosed with more cancers of the breast, endome-
can give an extra benefit in preventing cancer trium and ovary than women who do not use
(Latikka et al 1998). hormone therapy (Jaakkola et al 2009, Lyytinen
et al 2010, Koskela-Niska et al 2013). Linking
Exercise is also beneficial when rehabilitating the progesterone hormone to estrogen replace-
from cancer or in preventing a relapse (Knols ment therapy increases the risk of breast cancer,
et al 2005). Finnish BREX study concerning but protects against cancer of the uterus. The
this issue started in 2005 (Penttinen et al 2009). benefits of hormonal therapy during meno-
While nothing can yet be said of the cancer pause must be considered individually in rela-
prevention potential of exercise, this 12-month tion to the cancer risk.
aerobic jumping and circuit training interven-
tion completely prevented femoral neck bone Infections. Some viral infections increase can-
loss in premenopausal breast cancer patients cer risk. Infections caused by some bacteria
(Saarto et al 2012). may also increase risks of certain cancers. For
example, Helicobacter pylori increases the riskRisk factors for cancer and their effect | 21
of gastric cancer (Rehnberg-Laiho et al 2001). mune defence linked to the illness. In this situa-
Some tropical parasitic diseases also increase the tion, the HHV8 virus can cause Kaposi sarcoma.
cancer risk, but they are very unusual in Fin-
land. Socio-economic position
Human papilloma viruses (HPV) are the most The overall cancer incidence for working aged
researched virus family of those which cause can- men in the lowest social class is about one third
cer. Some cause chronic infection and, through higher than in the highest class. On the other
this, cervical cancer (Lehtinen et al 1996). Papil- hand, the cancer incidence for women is high-
loma viruses may also cause other cancers, such est in the highest social class. Typical cancers in
as pharyngeal cancer (Mork et al 2001). the lower class are those of the lip, stomach and
nose as well as throat and laryngeal cancer (Fig-
Vaccines aimed at preventing infections caused ure 5). In the lower classes, there are also more
by papilloma viruses have been on the market cervical cancers and vaginal cancers in women
for some years. Vaccine efficacies against low- and lung cancers in men. Cancers linked to a
grade cervical intraepithelial neoplasia (CIN) high standard of living are cancers of colon,
have been defined for both licensed vaccines breast and testis as well as melanoma of skin
(Lehtinen et al 2013). Ongoing studies with on the trunk and limbs. Differences in cancer
long-term follow-up will by 2015 and 2022 incidence between social classes may be as great
find out if HPV-vaccines also prevent higher as five-fold.
grades of CIN3 and invasive cervical cancer,
respectively (Lehtinen et al 2006, Rana et al Differences between social classes have increased
2012). rather than decreased (Pukkala and Weiderpass
1999 and 2002). The socio-economic pattern
An increased risk of liver cancer is also linked to can also change: for example, lung cancer in
chronic liver infection (hepatitis B and C viral women changed very rapidly from an illness re-
infections). The Hepatitis B virus (HBV) vacci- lated to a high standard of living to one related
nation campaign that began in Taiwan in 1984 to a low standard of living at the turn of 1980s.
led first to a reduction in HBV incidence and
then to a significant reduction in liver cancer Socio-economic position impacts on cancer risk
incidence in the age groups vaccinated (Chang through lifestyle and work-related factors. In
2011). most cancers in the lower social classes, smok-
ing is an important cancer risk factor. Smoking
HIV infection and AIDS are linked to an in- among men and young women in Finland is
creased risk of lymphoma and Kaposi sarcoma, most common in the lower social classes. For
which would otherwise be a very rare disease more than three decades, smoking differences
(Kaasinen et al 2013). These cancers are not have been accepted as explaining almost all of
caused directly by cancer-causing features of the the differences in the frequency of lung can-
HIV virus, but by the collapse of general im- cer and many other cancers between the social22 | Cancer in Finland
Figure 5
Connection of socio-economic position to cancer incidence in Finland 1971–2005. The graph is based
on information from NOCCA study (Pukkala et al 2009) and it shows standardized incidence ratios
(SIR) in relation to the population mean (1.0).
MEN
SIR
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Lip cancer Oesophageal Gastric Colon cancer Nose cancer Laryngeal Lung cancer Skin melanoma
cancer cancer cancer
WOMEN
SIR
1.6
• Higher level clerical employees
• Lower level clerical employees
1.4 • Unskilled
Skilled workers
• workers
1.2
• Farmers
1.0
• Economically inactive
0.8
0.6
0.4
0.2
0
Laryngeal Lung cancer Breast cancer Cervical Skin melanoma
cancer cancerRisk factors for cancer and their effect | 23
classes (Pukkala et al 1983). Dietary differences that the medicine being developed could cause
have been suggested to be related to social class cancer. The side effects of medicines that are al-
differences in cancer risk (Pukkala and Teppo ready on the market are monitored closely, and
1986). manufacturers remove products readily from
the market. However, it is unlikely that medi-
Cancer and other illnesses cines already in use nowadays or those which
are newly introduced new medicines have sig-
Generally, cancer risk is independent of that nificant cancer risks. For example the risks of
for other illnesses. For example, cancer risk cancer associated with the use of antibiotics and
does not increase in those with injuries from statins have been researched in Finland (Kilkki-
accidents or in those receiving treatment for nen et al 2008, Haukka et al 2010). At the mo-
heart ailments. Although lung cancer risk is ment, diabetes medicines are being researched
increased for people suffering from asthma for any possible impact on cancer risk. Pre-
(Vesterinen et al 1993), the risk is not caused liminary results suggest that, although diabetics
by asthma but by smoking, which causes both have an increased risk of getting cancer, there
illnesses. is no connection between diabetic medication
and cancer.
Depression, anxiety, grief and work-related
stress have little impact on cancer risk. Finnish Relatively toxic medicines and other treatments
schizophrenics have less cancer than the popu- which are used for treating complex illnesses are
lation average (Lichtermann et al 2001). Hip or a different matter. For example, radiation ther-
knee prostheses (Visuri et al 2010, Mäkelä et al apy for cancer, and some medical treatments,
2012) and silicone breast implants (Pukkala et may increase the risk of getting cancer later
al 2002 a) do not lead to an increased cancer (Kumpulainen et al 1998, Salminen et al 1999,
risk. Metayer et al 2000, Travis et al 1999, 2002,
2003, Dores et al 2002, Pukkala et al 2002 c,
Normal everyday ailments of the working age Gilbert et al 2003, Worrillow et al 2008, Jakobs-
population, such as headache, tiredness, diar- son et al 2011, Morton et al 2011). However, the
rhoea, weak spells or anaemia connected to the benefits of these types of cancer treatment have
menstrual cycle, are not normally associated been estimated to be greater than their adverse
with cancer, although they can sometimes be effects.
symptoms of cancer. Epilepsy does not increase
the risk of cancer, but epilepsy can be a symp- The body’s immune system must be suppressed
tom of a hidden brain tumour (Lamminpää et for organ transplants, so that the transplanted
al 2002). organ will not be rejected. Because the immune
system protects against cancer, the cancer risk
Medicines are tested in clinical research before for people who have received kidney or liver
they are used. Research and development work transplants, for example, is above average (Bir-
is stopped if there are even small indications keland et al 1995, Åberg et al 2008). The virus24 | Cancer in Finland
causing HIV infection and AIDS suppresses to which tobacco and diet were both responsi-
the immune system and increases the risk of ble for one third of cancer deaths in the United
cancer. The body’s disturbed immune system States (Doll and Peto 1981). According to Nor-
in rheumatic illnesses (Kauppi et al 1997, Hill dic estimates (Olsen et al 1997) tobacco causes
et al 2001), in certain intestinal tract and skin only about 15 percent of new Finnish cancer
ailments (Collin et al 1996) as well as in carti- cases. The difference is explained, among other
lage-hair hypoplasia (Mäkitie et al 1999) also things, by the fact that lung cancer is a disease
increase the cancer risk. with a poor prognosis and its proportionate
share of cancer deaths is therefore bigger than
Many genetic syndromes also include cancers its share of cancer incidence. The significance
as one aspect, sometimes giving rise to several of various factors also differs according to re-
tumours in different organs. For some inherited gional and local circumstances, health behav-
illnesses, the cancer risk is increased, although iour and socio-economic situation.
cancer itself does not belong to the group of
symptoms. For example Down syndrome is Possibilities for cancer
linked to an increased risk of leukaemia (Patja
prevention
et al 2006).
It is in principle possible to attempt to prevent
Getting one cancer does not protect against cancer at different phases of the chain of events
other cancers. Cancer patients can develop new leading to the disease. We may affect the factors
cancers just like healthy people. According to that begin the process, or its progression, by
the data of the Finnish Cancer Registry, among helping the body to correct early changes or by
those who have recovered from the first cancer treating early stages of disease before the actual
about one in ten gets a new cancer (Sankila et al cancer has developed.
1995). The factors causing the first cancer can
also increase the risk of the second cancer: for The possibility of preventing cancer depend on
example patients with laryngeal cancer have an whether it is possible to change cancer risk fac-
increased risk of getting lung cancer (Teppo et tors related to environment and lifestyle. It was
al 1985). estimated in 1980 that the annual number of
lung cancer cases in men would decrease from
Attributable fractions 2000 cases, at that time, to a few hundred if all
Finns stopped smoking immediately (Hakuli
of risk factors
nen and Pukkala 1981). Smoking did not stop
There have been attempts to put the population completely, but has decreased so much that the
attributable fractions of different cancer-related age-adjusted incidence of lung cancer has fallen
factors in order of importance. The most well- to less than half of the highest level in 1970s.
known estimate of the contribution of environ- According to estimates, the incidence of lung
mental and other causes to the risk of cancer is cancer will continue to decrease up to the year
the study of Doll and Peto in 1981, according 2020 (see page 65).Risk factors for cancer and their effect | 25
Finland was the first country to add tobacco alcohol, salt and mouldy products should be
smoke to the list of carcinogenic substances limited. Artificial dietary supplements should
and, in its legislation, states that tobacco smoke not be used.
causes cancer. The aim of the tobacco law of
2010 is to stop smoking in Finland by the year The development of cancer normally requires
2040. If this happened, it would have a great a long time. Any current changes in exposure
impact on the incidence of lung and other can- will mainly impact on cancer risk after the
cers. 2020s. Although significant changes in cancer
incidence cannot be expected in the coming
The potential of reducing other risk factors decades, deaths from cancer can be reduced
does not look as promising. For example, the through the development of methods for early
cancer-causing and cancer-protective charac- cancer detection and improvement in treat-
teristics of food products are not well enough ments, amongst others. An excellent example
known for cancer risk to be reduced through of cancer prevention is the systematic screening
specific changes in eating habits. The knowl- of cell changes in the cervix by the Pap test and
edge of many other risk factors is equally insuf- the treatment of these cell changes, which has
ficient and inaccurate. dramatically reduced cervical cancer in Finland
(see page 50).
Recently, many have begun to consider increas-
ing exercise as a significant method of cancer There are excellent conditions in Finland for
prevention. For example, the European rec- carrying out epidemiologic research on cancer
ommendations on cancer prevention (Boyle et risk factors. A well-functioning personal identi-
al 2003) list avoiding obesity and taking daily ty code system makes it possible for information
exercise as the second most important practi- collected from different sources to be combined
cal steps in cancer prevention. Only refraining reliably (Pukkala 2011). In addition, Finnish
from smoking is more important. The World legislation allows the combination of informa-
Cancer Research Fund and the American Can- tion from different registries, for scientific stud-
cer Society published in 2007 the recommen- ies that will benefit society and individuals. For
dations of an extensive group of experts on example, research on dietary factors, the risks
reducing the risk of cancer through diet and of living in certain areas, working environ-
exercise. The recommendations and justifica- ments, heritable factors and the inequality of
tions can be found on the Internet (www.di- social groups have all been based on combining
etandcancerreport.org). The messages of most information from registries. It is of the utmost
dietary recommendations are similar: they un- importance that the possibility of doing high
derline the importance of staying as slim as pos- quality epidemiologic research is safeguarded
sible, as long as weight remains within normal when cancer research becomes more and more
limits. Exercise should be taken every day. Diet complex and requires detailed information.
should be mainly of vegetable origin. Intake of Then the co-operation of several information
high-energy foods, red meat, meat products, providers is needed even more than before.26 | Cancer in Finland
Frequency of cancer in Finland
Other 661 Stomach 1 189
Currently in our country there are 250 000
people who have had cancer at some point in
their lives. Some of them are fully recovered;
Kidney 70
some of them have a problem or side-effect Leukaemia 83
caused by the disease or its treatment. The Central nervous system 84
Rectum 91 MEN
number of prevalent cancer patients is continu- Bladder 92 1953
ously increasing. Colon 94
Pancreas 96
Larynx 99
In 2011 more than 30 000 new cancer cases Lip 132
were diagnosed in Finland. The most common Oesophagus 150
cancer in women was breast cancer and in men Prostate 204 Lungs 903
prostate cancer. Nearly 4 900 women got breast
cancer and over 4 700 men got prostate cancer
(Figure 6). More than 3 000 intestinal tract can-
cers were found for men and women combined.
Only 656 cases of gastric cancer, which was the
most common cancer for both men and wom-
en in the 1950s, were detected. Statistics on the
amount of cancer cases and cancer deaths are
given by age group and health districts on the
website of the Finnish Cancer Registry (www. Stomach 1 000
cancerregistry.fi, section Statistics). Other 833
About 11 700 Finns die of cancer annually,
making cancer the main cause of every fifth Skin, non-melanoma 73
Finnish death. The number of cancer deaths Pancreas 82 WOMEN
has remained quite stable for a long time. The Leukaemia 84 1953
Lung 87
commonest cause of cancer death is lung cancer Central nervous system 97
(Figure 7). Rectum 110
Ovary 150 Breast 613
Changes in cancer frequency Colon 150
Oesophagus 153 Cervix 318
Uterus 243
Cancer is a disease which becomes more com-
mon with increasing age (Figure 8). AlthoughFrequency of cancer in Finland | 27
Figure 6
Number of cancer cases for men and women in 1953 and 2011. The surface area of the circle
describes the total number of cancer cases.
Larynx 104 Other 1 147
Pharynx 108
Soft tissues 109
Testis 134
Thyroid 137
Oesophagus 196
Multiple myeloma 197
Liver 292
Prostate 4 719
Leukaemia 312
Stomach 376
Central nervous system 400
MEN
Pancreas 473
2011
Kidney 563
Rectum 623
Lung 1 570
Non-Hodgkin lymphoma 651
Skin melanoma 655
Bladder 731 Colon 876
Skin, non-melanoma 808
Other 1 265
Soft tissues 129
Gallbladder 132
Liver 156
Cervix 168
Multiple myeloma 171
Bladder 215
Stomach 280
Breast 4 865
Leukaemia 285
Thyroid 314
Kidney 417
WOMEN
Ovary 433
2011
Rectum 436
Non-Hodgkin lymphoma 533
Pancreas 540
Colon 874
Central nervous system 600
Uterus 859
Skin melanoma 664
Skin, non-melanoma 791 Lung 82428 | Cancer in Finland
Figure 7
Number of deaths caused by cancer in Finland in 2011.
Other 1 602
Lung 2 100
Gallbladder 220
Skin melanoma 223
Oesophagus 231
Multiple myeloma 258
Colon and rectum 1 152
Bladder 283
Leukaemia 328
Ovary 360
Liver 74
Pancreas 1008
Central nervous system 399
Kidney 420
Prostate 886
Non-Hodgkin lymphoma 476
Stomach 499 Breast 844Frequency of cancer in Finland | 29
Figure 8 /100 000
Cancer incidence and mortality 5 000
per 100 000 person-years by age group
• Men, incidence
in Finland in 2005–2011.
4 000
• Men, mortality
3 000
2 000
• Women, incidence
• Women, mortality
1 000
Figure 9
0
Trends of annual numbers in new cancer cases
0 20 40 60 80 100 Age
and cancer deaths in Finland in 1953–2011.
Number of cases
16 000
• Men, new cases
14 000
• Women, new cases
12 000
10 000
8 000
6 000 • Men, cancer deaths
• Women, cancer deaths
4 000
2 000
0
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Year30 | Cancer in Finland
the number of those getting cancer annually increased at first and then reduced as smoking
has increased over three-fold in 50 years (Figure declined. The same phenomenon is seen, but
9), this increase does not describe changes in slightly less marked, in the incidence of pancre-
the risk of getting cancer. Population increase, atic cancer (Figure 12). Developing lymphoma
particularly in older age groups, also has an im- is linked, among other things, to the reduced
pact on the growth in case numbers. functioning of the immune system. This hap-
pens, for example, when many serious illnesses
Cancer risks at different time periods, in different are treated successfully. This phenomenon may
regions and populations, can be made compara- explain the increasing risk for lymphoma at the
ble using age-standardization. Figure 10 shows population level. The incidence of lip cancer
trends in the age-standardized cancer incidence has decreased heavily, reflecting the fact that
and mortality rate for all cancers over the years. Finns have moved to indoor work and that their
In the absence of population aging, the annual exposure to sunlight and tobacco has reduced.
number of cancers would have stayed approxi-
mately the same, if breast cancers detected by The risk of breast cancer in women has in-
screening and prostate cancers detected by PSA creased continuously, and breast cancer is now
tests were excluded from the figures. The age- the most common cancer among women (Fig-
standardized cancer mortality is now only one- ure 11). The occurrence of breast cancer in-
half the rate of the peak years. creased by about one-tenth in 1987, when the
national mammographic screening programme
Gastric cancer, which was the most common for breast cancer began (see page 52). More
cancer in men and women up to the 1950s, has than one thousand breast cancers are detected
decreased during the whole period of cancer annually through screening, most of which are
registration (Figure 11). Since the 1950s, lung asymptomatic. Another significant reason for
cancer in men has increased dramatically, as the increase in breast cancers is hormone treat-
men had started smoking during the war in the ment of menopause (Jaakkola et al 2009, Lyyti
early 1940s. Thereafter, smoking among men nen et al 2010). The reduction of lengthy hor-
has decreased, which can be seen as a reduced mone therapy at the beginning of 2000s is seen
lung cancer risk. The risk of prostate cancer has clearly in a decrease in breast cancer incidence
increased steadily since the early 1990s. Since in Norway and Sweden, with a smaller decrease
then, PSA testing, used in the early diagnosis of in Finland (Hemminki et al 2008).
prostate cancer, has become increasingly com-
mon. This has increased the detection rate of The increase in the risk of cancer of corpus
prostate cancer so strongly up to the year 2005 uteri ended in the 2000s (Figure 11). This phe-
(Figure 11)), that it has produced an overall in- nomenon is partly explained by the fact that
crease in the incidence of all cancers (Figure 10). the uterus has been removed from nearly one-
third of all 70-year old women, and that there
Of the more rare cancers among Finnish men, is no longer a risk of cervical cancer (Luoto et
for example, the incidence of bladder cancer al 2004). No clear reasons have been found forYou can also read
